Method and apparatus for testing aircraft electrical systems

ABSTRACT

A method, and corresponding apparatus, for testing an aircraft control system is disclosed. The method includes simultaneously coupling a test device to a plurality of separate test points in an aircraft control system, selecting each test point individually such that the test device is enabled for electrical connection with the selected test point, conducting a test on the control system at each selected test point using the test device, detecting a signal or voltage at the selected test point, and indicating a result of the test at the selected test point to an operator.

FIELD OF THE INVENTION

The present invention relates to a testing method and apparatus, andmore particularly, to a method and apparatus for testing the operabilityof one or more electrical system in an aircraft.

BACKGROUND OF THE INVENTION

Modern aircraft, and particularly larger commercial aircraft, are highlysophisticated vehicles incorporating numerous electrical systems forensuring vehicle control and safety. During the assembly andcommissioning of a new aircraft, it is necessary to ensure that themultitude of electrical circuits in the various control and safetysystems of the aircraft are connected and operating correctly.

The testing and evaluation of the various control and safety systemsduring the assembly of an aircraft conventionally involve conducting aparticular test procedure at a number of different test points. In otherwords, essentially the same procedure must be repeatedly carried outtime and again at each of the series of test points. This may, forexample, involve the testing of a particular avionic unit at multipleconnection or input points to determine whether or not a defined voltageexists at each input. A significant drawback of such a testing regime isthat the execution of the tests is extremely time intensive, andtherefore cost intensive, because it involves manually checking each ofthe various test points one after the other. This requires that testequipment be positioned at different locations and that a new contact orconnection be established at each of the different test points.Furthermore, with a large number of separate test points, the risk thatone or more test point may be overlooked also becomes significant insuch a conventional testing regime.

Thus, it is an object of the present invention to provide a method andapparatus for testing aircraft control and safety systems which aresimpler to implement and are optimized from a time and cost perspective.It is a further object of the invention to provide such a method andapparatus that may reduce the risk of a test point being overlooked ormissed.

SUMMARY OF THE INVENTION

According to one aspect, the present invention provides a method oftesting an aircraft electrical system, comprising the steps of:

-   -   simultaneously coupling a test device to a plurality of separate        test points in an aircraft electrical system;    -   individually selecting any one of the plurality of test points,        such that the test device is enabled for electrical connection        with the selected one of the plurality of test points; and    -   conducting a test on the electrical system at that one of the        plurality of test points selected with the selector means using        the test device.

The above expression “enabled for electrical connection” is to beunderstood as meaning that the potential for electrical current flowexists, although it may be that a certain threshold voltage would benecessary across the connection before any current would be able toflow.

The method of the invention typically comprises the step of individuallyselecting each of the plurality of test points of the electrical system,one after the other, such that all of the test points of the electricalsystem are tested in series. The number of test points is preferably atleast three, more preferably in the range of four to ten, and may evenbe as many as twenty or more.

In a preferred form of the invention, the method includes the step ofconsolidating the test points of the electrical system into a group andarranging the test points in that group to be simultaneously coupled tothe test device. In a preferred form of the invention, the coupling stepof the method comprises simultaneously coupling a plurality of connectorelements of the test device to the plurality of separate test points inthe aircraft electrical system

Thus, the present invention provides a new testing regime thatsignificantly improves upon the conventional method. In particular, asignificant advantage of the present invention is the enormous saving intime and effort which is realized by the user not having to move his/hertesting equipment to different test points at different locations aroundthe aircraft and then establish a new connection at each of the varioustest-points. The invention thus enables the testing to occur much moreefficiently by simultaneously coupling the test apparatus to an entiregroup of test points of the electrical system at a single location andthen individually selecting and testing each point of the system, oneafter the other.

In a preferred form of the invention, the step of conducting a test onthe electrical system includes detecting one or more signal at the testpoint of the electrical system selected with the selector means. Forexample, the detecting step may include detecting whether or not adefined voltage exists at the selected test point.

In a preferred form of the invention, the method further comprises thestep of: indicating a result of the test at the selected test point toan operator. For example, the indicating step may include providing avisual indication of the test result, and preferably comprisesilluminating and/or not-illuminating a lamp or a light-emitting diode(LED) to indicate the state of the electrical system at the selectedtest point.

In a preferred form of the invention, the method further comprises thestep of: measuring a property of a signal detected at the selected testpoint of the electrical system. In addition, the method may furthercomprise the step of: generating one or more test signal as an input tothe selected one of the test points of the electrical system.

According to another aspect, the present invention provides an apparatusfor implementing the method of the invention described above. Indeed,the nature of the inventive method will become clearer from thefollowing description of the apparatus. In particular, the inventionprovides an apparatus for testing an aircraft electrical system,comprising:

-   -   connector means for simultaneously coupling the apparatus to a        plurality of separate test points in an aircraft electrical        system; and    -   selector means adapted to individually select any one of the        plurality of test points, such that the apparatus is enabled for        electrical connection with the selected one of the plurality of        test points;    -   wherein the apparatus is adapted to test the electrical system        at any one of the plurality of test points selected with the        selector means.

In a preferred form of the invention, the connector means comprises aplurality of connector elements for simultaneously coupling the testapparatus to the plurality of separate test points in the aircraftelectrical system. In particular, the test points may be arranged indiscrete groups, with each group having its own connector element. Eachgroup of test points may, for example, correspond to a particularfunction or operation of the aircraft electrical system. In one form ofthe invention, the plurality of separate test points may correspond to aplurality of signal input points for the aircraft electrical system. Forexample, the electrical system may be an aircraft control systemcomprising a processor having multiple input points for control signals,e.g. sensor signals or feedback signals, which provide the processorwith information on the state of the aircraft. In that case, therefore,the connector means may comprise a plurality of connector elements forsimultaneously coupling the apparatus to all of the input points of theprocessor in the aircraft electrical system. The apparatus may thusdetermine whether the input points of the control system are in theproper condition for receiving signals.

In another form of the invention, the plurality of separate test pointsmay correspond to a plurality of separate circuits of the electricalsystem. Accordingly, the connector means comprises a plurality ofconnector elements for simultaneously coupling the test apparatus to theplurality of separate circuits of the system such that the testapparatus may determine whether the circuits are connected and operatingcorrectly.

In a preferred form of the invention, the selector means comprises aswitching device for selectively switching the test apparatus intoelectrical connection with any one of the plurality of test points.Preferably, the switching device is designed to be manually operated bythe user, although remote-controlled operation is also contemplated bythis invention. The switching device may include a rotatable dial and/ora push-button type switching arrangement.

In a preferred form of the invention, the test apparatus comprisesdetector means for detecting one or more signal at the test point of theelectrical system selected with the selector means. For example, thedetector means may be designed to detect whether or not a definedvoltage exists at the system test point selected with the selectormeans. In this way, the detector means of the apparatus may conduct thetest on the electrical system at the selected test point.

The detector means of the test apparatus preferably includes indicatormeans for indicating the result of the test at the selected test pointto a user operating the apparatus. The indicator means is typicallyadapted to provide a visual indication of the test result, and may forexample comprise a lamp or light-emitting diode (LED), the illuminationor non-illumination of which indicates a particular state of theelectrical system at the selected test point. Alternatively, oradditionally, the indicator means may provide an audible indication ofthe test result.

In a particularly preferred form, the detector means may also be adaptedto measure a signal detected at the selected test point of theelectrical system. In this regard, the detector means may comprise ameter for measuring, for example, a voltage detected at the selectedtest point.

In a preferred form of the invention, the test apparatus may furthercomprise signal means for generating one or more test signal as an inputto the selected one of the test points of the electrical system. Forexample, the signal means may be adapted to generate a single testsignal for input at each of the selected test points. Alternatively, thesignal means may be adapted to generate a plurality of different testsignals for input at the selected test points. Accordingly, the selectormeans may be adapted to select one of the plurality of test signals andto input the selected test signal to the selected test point of theelectrical system.

As noted above for the method, the apparatus of the invention providesmajor savings in time and effort during the testing of aircraftelectrical systems because there is no need for the user to move his/hertesting equipment to access different test points at different locationsaround the aircraft. Furthermore, there is no need to manually establisha new connection with each of the various test-points in order to carryout each individual test. The testing is therefore much more efficientin terms of both time and cost, and the risk of missing or overlooking aparticular test point is also significantly reduced, because theswitching device of the apparatus can provide serial switchingarrangement for selection of each of the test points. In addition, theapparatus of the invention provides a straight-forward means for givingthe user an immediate visual indication of the test result.

The present invention will now be described by way of example withreference to particular embodiments illustrated in the accompanyingdrawings. It should be understood, however, that the followingdescription of preferred embodiments is not intended to limit thegenerality of the inventive concept as described above or as defined inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are hereafter described withreference to the accompanying drawing figures, in which like referencecharacters designate like features, and in which:

FIG. 1 is a schematic perspective view of a commercial aircraftillustrating the locations of the wing flaps and wing slats;

FIG. 2 is a schematic front perspective view of a test apparatusaccording one embodiment of the present invention;

FIG. 3 is a schematic rear perspective view of the test apparatus shownin FIG. 2; and

FIG. 4 is a circuit diagram for the test apparatus shown in FIGS. 2 and3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is designed for testinga control system for controlling the operation of aircraft wing flapsand wing slats. With reference to FIG. 1 of the drawings, the flaps F ofan aircraft are hinged surfaces mounted at the rear or trailing edge ofeach wing towards the body of the aircraft. The flaps F are able to bedeflected downwards to increase the wing curvature and thereby generateadditional lift for low speed, high angle of attack flight, which istypical during landing. Similarly, the slats S of the aircraft are smallaerodynamic surface extensions mounted on the front or leading edge ofeach wing, which are extendable to generate additional lift and allowthe wing to operate at higher angles of attack. The slats S aretypically deployed during take-off and landing but are usually retractedduring cruising flight.

The control of the flaps F and slats S of an aircraft typically occurshaving regard to signals output by a Feedback Position Pickoff Unit(FPPU) and an Asymmetry Position Pickoff Unit (APPU). The signals of theFPPU provide information about the position of the flaps and slats andthe signals of the APPU provide information about asymmetries betweenthe starboard or right-hand (RH) wing and the port or left-hand (LH)wing. A control processor is employed to read out the signals of theFPPU and the APPU. In the course of ground tests of the aircraft, e.g.during assembly or commissioning, it is necessary to test theFPPU-inputs and the APPU-inputs of the control processor. In particular,it is necessary to check whether a particular voltage exists at theseinputs, which corresponds to an actual flap/slat angle or position. Thisparticular or defined voltage is read out by an angle measuring device.

To this end, the present invention provides a test apparatus 1 and acorresponding test method as will now be described with reference to thedrawing FIGS. 2 to 4. In particular, the FPPU-inputs and the APPU-inputsof a control processor are arranged and consolidated for plug-in typecoupling to a connector unit 10 of the test apparatus 1. The connectorunit 10 comprises a portable casing 11 having a handle 12 on its rearside for ease of carrying. On its front side, the casing 11 of theconnector unit 10 presents a number of connection elements 13 in theform of plug-in type sockets for coupling to the FPPU-input points andthe APPU-input points of the control processor.

Furthermore, the test apparatus 1 comprises a hand-held selector unit 20for individually selecting any particular one of the FPPU-input pointsand the APPU-input points of interest to be tested. In this regard, itis to be noted that the control processor of the aircraft flap-slatcontrol system has (i) an FPPU-input point, a RH APPU-input point and aLH APPU-input point for the flaps F, and (ii) an FPPU-input point, a RHAPPU-input point and a LH APPU-input point for the slats S. Accordingly,at a front face 21 of the selector unit 20, a rotatable dial-typeswitching device 22 is provided with discrete switch positions 24. Theswitch positions are labeled to show how the dial 22 should be rotatedto select the processor input points for control of the slats S on the“SLAT” side of the front face 21, and the processor input points forcontrol of the flaps F on the “FLAP” side of the front face. When thedial is rotated to select a particular FPPU- or APPU-input (i.e. testpoint) of the control processor, an electrical connection between theapparatus 1 and the selected test point of the processor is enabled.

The selector unit 20 is operatively connected to the rear side 14 of theconnector unit 10 via a cable 15, which may be provided in any suitablelength. As can be seen in FIG. 2 of the drawings, the front face 21 ofthe selector unit 20 includes an indicator device or display 25 showingthe word “OFF”. When the defined voltage (which corresponds to theflap/slat position) is detected at the selected input point (i.e. testpoint) of the control processor, this indicator device 25 may bedesigned to display an appropriate word, such as “ACTIVE”, oralternatively to simply illuminate.

As can be seen in the circuit diagram shown in FIG. 4, the apparatus 1includes sets of relay switches 26 for enabling a connection to each ofthe multi-circuit inputs of the processor CP. The circuit diagram inFIG. 4 illustrates the indicator device 25 as comprising a lamp orlight-emitting diode (LED), which is designed to illuminate when adefined voltage is detected at the selected test point. In this way, thelamp or LED 25 serves as a detector for detecting whether or not adefined voltage exists at the selected test point, and simultaneously asan indicator of the test result to the user of the apparatus. Thus, whena user operates the selector unit 20 to select the individual testpoints of the processor by rotating the dial-type switch 22, the userreceives an immediate indication from the LED or the display 25 as towhether or not the test point is in a satisfactory state.

Advantageously, the method and the apparatus 1 of the invention onlyinvolves a single connection operation to the processor, and the variousinputs of the processor for control of both the flaps F and slats S canbe checked in series in a simple and efficient manner by rotating theswitching device 22 and observing the indicator device 25.

It will be appreciated that various alterations and/or additions may bemade to the features of particular embodiment of the method andapparatus of the invention described above with reference to thedrawings without departing from the scope of the invention as defined inthe appended claims.

In this regard, another embodiment of the invention that is notspecifically illustrated in the drawings concerns an application of theapparatus and method to the testing of an aircraft fire safety system.In particular, an aircraft fire safety system typically includes anumber of fire detection circuits or “loops” which, in the event of afire, are designed to generate an electrical signal that may effect awarning signal in the cockpit and/or may activate a fire-extinguishingsystem. The fire detection loops typically comprise wax-coated cables.Under the elevated temperatures caused by a fire (and set at apredetermined threshold), the wax coating melts such that the cablescome into contact with the outer shell of the aircraft and this, inturn, results in the generation of the electrical signal.

In the course of ground tests, it is necessary to check whether the firedetection loops of an aircraft fire safety system are properly connectedto form closed circuits and do not have any breakages or discontinuitiesresulting from cable damage. Thus, an apparatus and method embodying thecentral concepts of the invention could be employed to test thecontinuity of each of the fire detection loops, selectively andserially, one after the other. In this regard, an apparatus according tothe invention could be coupled to a unit for receiving the signals ofthe fire detection loops, such that the output of each of the firedetection loops to that signal receiving unit forms a separate testpoint. The outputs of each circuit could then be individually selectedand tested using the apparatus and method of the invention to check theintegrity of each loop.

A further embodiment of the invention not illustrated in the drawingsconcerns an application of the apparatus and method of the invention tothe selective testing of the individual channels of an aircraftcommunication system. Again, the channels of the communication systemshould form complete circuits, such that the integrity of each channelcould be evaluated in similar fashion.

The invention claimed is:
 1. A method of testing an aircraft controlsystem, comprising the steps of: coupling a plurality of connectionelements of a portable connector unit of an apparatus for testing anaircraft control system to a plurality of separate input points in theaircraft control system to be tested; operatively connecting a hand-heldselector unit to the connector unit via a cable, wherein the hand-heldselector unit comprises a series switching device, and a detector andindicator device; serially selecting individual ones of each of theplurality of separate input points in the aircraft control system to betested by actuation of the series switching device of the hand-heldselector unit to provide an electrical connection between the selectedone of the plurality of separate input points in the aircraft controlsystem to be tested and the hand-held selector unit, wherein all of theplurality of separate input points in the aircraft control system to betested are individually tested one after the other in a series; anddetecting and indicating whether a defined voltage exists at theselected one of the plurality of separate input points in the aircraftcontrol system to be tested using the detector and indicator device ofthe hand-held selector unit.
 2. A method according to claim 1, furthercomprising the step of: generating one or more test signal(s) as aninput to the selected one of the plurality of separate input points inthe aircraft control system to be tested.
 3. An apparatus for testing anaircraft control system, the apparatus comprising: a portable connectorunit provided with a plurality of connection elements for simultaneouslycoupling the portable connector unit to a plurality of separate inputpoints in the aircraft control system to be tested; and a hand-heldselector unit having a series switching device and a detector andindicator device, wherein the hand-held selector unit is operativelyconnected to the connector unit via a cable, and the series switchingdevice is configured to serially select individual ones of each of theplurality of separate input points in the aircraft control system to betested in a series to provide an electrical connection between theselected one of the plurality of separate input points in the aircraftcontrol system to be tested and the hand-held selector unit, and whereinthe detector and indicator device is configured to provide a signal whena defined voltage exists at the selected one of the plurality ofseparate input points in the aircraft control system to be tested.
 4. Anapparatus according to claim 3, wherein the series switching deviceincludes a rotatable dial and/or a push-button type switchingarrangement.
 5. An apparatus according claim 3, comprising signal meansfor generating one or more test signal(s) as an input to the selectedone of the plurality of separate input points in the aircraft controlsystem to be tested.